A pair of circularly permutated PDZ domains control RseP, the S2P family intramembrane protease of Escherichia coli.
The sigma(E) pathway of extracytoplasmic stress responses in Escherichia coli is activated through sequential cleavages of the anti-sigma(E) protein, RseA, by membrane proteases DegS and RseP. Without the first cleavage by DegS, RseP is unable to cleave full-length RseA. We previously showed that a PDZ-like domain in the RseP periplasmic region is essential for this negative regulation of RseP. We now isolated additional deregulated RseP mutants. Many of the mutations affected a periplasmic region that is N-terminal to the previously defined PDZ domain. We expressed these regions and determined their crystal structures. Consistent with a recent prediction, our results indicate that RseP has tandem, circularly permutated PDZ domains (PDZ-N and PDZ-C). Strikingly, almost all the strong mutations have been mapped around the ligand binding cleft region in PDZ-N. These results together with those of an in vitro reaction reproducing the two-step RseA cleavage suggest that the proteolytic function of RseP is controlled by ligand binding to PDZ-N.
Inaba
Kenji
K
Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
Suzuki
Mamoru
M
Maegawa
Ken-ichi
K
Akiyama
Shuji
S
Ito
Koreaki
K
Akiyama
Yoshinori
Y
D018360:Crystallography, X-Ray / Q000379:methods; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D005786:Gene Expression Regulation; D006639:Histidine / Q000737:chemistry; D008024:Ligands; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008957:Models, Genetic; D008958:Models, Molecular; D008968:Molecular Conformation; D009154:Mutation; D019897:Periplasm / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013997:Time Factors
D029968:Escherichia coli Proteins; D008024:Ligands; D008565:Membrane Proteins; D006639:Histidine; D010450:Endopeptidases; C440001:RseP protein, E coli